The solubilities of benzoic acid in supercritical CO2 with pure and mixed cosolvent were measured at pressures from 8.0 to 23.0MPa and 328. 15Kfor pure cosolvent, and 308. 15, 318. 15 and 328. 15Kfor mixed cosolvent. The experiments were carried out by using a flow-type phase equilibrium apparatus. The effect of cosolvents, ethyl acetate, ethanol and ethyl acetate + ethanol (molar ratio 1:1) was studied at the concentration of 2.0 mol%. The results showthat the solubility enhancement follows the order: ethanol > ethyl acetate + ethanol > ethyl acetate. The measured solubilities were correlated using a modified Chrastil equation, and the calculated results are in good agreement with the experimental data.

The solubilities of p-nitrobenzoic acid in supercritical carbon dioxide and carbon dioxide + cosolvents were determined at (308, 318, and 328) K and over the pressure range from (8.0 to 21.0) MPa. The effect of cosolvents, cyclohexane, ethanol, cyclohexane + acetone (equal-molar mixture), and acetone on the solubility of p-nitrobenzoic acid was studied at a mole fraction of 3.0 % (cosolvents in supercritical mixtures). The solubility data in supercritical carbon dioxide in the absence and presence of cosolvents were correlated by the equations proposed by Mendez-Santiago and Teja with satisfactory agreement, respectively.

The solubilities of pure and equal-molar mixed o-phthalic acid and p-aminobenzoic acid in supercritical carbon dioxide, were determined at 308.15, 318.15, and 328.15 K, and over the pressure range from 8.0 to 21.0MPa. The solubility of a given solid in a ternary system increased relative to the value of the corresponding binary system, and was in proportion to the solubility of the other solid in the ternary system. The selectivity of supercritical carbon dioxide to the solid mixture increased with the increasing temperature. The model proposed by Mendez-Santiago and Teja was applied using statistical software to correlate the solubility data of both binary and ternary systems with good results.

The solid solubility of propyl p-hydroxybenzoate was measured for the first time in supercritical carbon dioxide at temperatures of (308.15, 318.15 and 328.15) K and pressures from (8.0 to 23.0) MPa. The influence of cosolventsscyclohexane, cyclohexane + acetone (molar ratio 1:1), and acetoneswas studied at a mole fraction of 0.035. The data were obtained by using a flow-type phase equilibrium apparatus, which was further tested by measuring the solubility of benzoic acid in compressed CO2. The measured solubilities in supercritical CO2 without and with cosolvents were correlated using the Chrastil equation and the modified Chrastil equation, respectively.

The solubility of 2-naphthol and anthracene in supercritical CO2 was determined at 308.1, 318.1 and 328.1 K, with and without cosolvent. The influence of three polar or nonpolar cosolvents, acetone, ethanol and cyclohexane, was studied at concentrations of 3.6 and 4.0 mol%. The solubility enhancement with these cosolvents is considerable, and the cosolvent effect increases in the order ethanol, acetone, and cyclohexane for 2-naphthol and for anthracene, the order is cyclohexane, ethanol, and acetone. The influence of density and cosolvent on the solid solubility was studied and discussed.